Fuel combustion indicator



United States Patent Inventors Shigeo Kuwayama and Mikihiko Yagi, Kanagawa, Japan Appl. No. 806,229 Filed March 11, 1969 Patented Oct. 27, 1970 Assignee Fuji Photo Film Co., Ltd.

Kanagawa, Japan Priority March 30, 1968 Japan 43/25,233

FUEL COMBUSTION INDICATOR 9 Claims, 4 Drawing Figs.

Int. Cl G0ld 21/00 Field of Search 1 16/114,

28, 1 1410; 73/355; 356/46; 431/4, 13- 17; 240/1El1250/con5u1ted; 350/96 References Cited UNITED STATES PATENTS Furo Marcellus Bucknam et a1 Peter ct a1 Nitzberg Clark Egan et a1. Duke Ray etal..... Schmidt Primary Elmminer Louis J. Capozi Att0rneySughrue, Rothwell. Mion, Zinn & Macpeak 240/8.4 73/355 73/355X 240/1X 116/28 431/13X 116/114 73/355 431/15 116/114 ABSTRACT: A heat-resisting and oxidation-proof metallic member is positioned within the fuel combustion area and spaced from a light transparent body which transmits the red color of the metallic member during fuel combustion to a viewer at the other end of the transparent body.

Patented Oct. 27, 1970 FIG. 2

HG. I

INVENTORS.

SHIGEO KUWAYAMA MIKIHIKO YAGI Mj W ATTORNEYS.

FUEL COMBUSTION mnrcxroa BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to devices for indicating combustion of fuel and the presence of a flame and more particularly to a device which readily indicates whether or not a gaseous, liquid or solid fuel is, in fact, burning.

2. Description of the Prior Art The harmful nature of burnt waste gas to humanity has recently become a very serious social problem. It has become extremely important, in view of the harmful nature of the waste gas, in addition to the problem of heat control, to isolate the combustion chamber and the discharging mechanism for the waste gas, in a combustion apparatus to prevent the waste gas from being diffused into the ambient atmosphere and from reaching the human body. Various measures have been developed to discharge the waste gas from combustion apparatus. An imperforate waste gas conducting channel or wall means is normally provided for preventing the waste gas from being diffused but this prevents the combustion flame within the combustion apparatus from being visually observed in a direct manner by the operator.

In such cases, it is conventional to provide a peephole in the combustion apparatus adjacent the combustion chamber allowing direct visual observation of the combustion flame. However, the disadvantage exists that the direction of observation of the flame is highly restricted. Alternatively, a transparent rodlike body made of a material such as glass, quartz glass or crystalline glass and having one end pointed to form a cone-shaped tip has been used for directly observing the combustion flame. In this case, the cone-shaped tip of the transparent rodlike body is inserted into the flame whereby, upon heating of the tip, light is emitted which is transmitted from the tip to the other end of the rodlike body and readily observed by the viewer. However, the tip of the rodlike body is softened and deformed and the optical qualities of the tip are changed by the heat with the rod tip end tending to lose its transparency and is further subject to being broken. The increase in temperature of the glass rodlike body is rather slow which is an additional disadvantage, in that it takes a relatively long time for the tip to become heated to light-emitting condition. Thus, combustion of the fuel is actually taking place without a visual indication of the same.

SUMMARY OF THE INVENTION The present invention provides a novel and useful device for indicating the combustion of fuel where the flame in the combustion chamber of the combustion apparatus may be directly viewed from any desired direction. The indicating device responds without substantial delay so as to immediately indicate any combustion of fuel actually taking place in the combustion apparatus. The indicator of the present invention may be used for a long period of time without deterioration in the performance of the device.

The device of the present invention is characterized by the employment of a transparent rodlike body made of a ceramic material such as crystalline glass and the like and a heat-resisting and oxidation-proof metallic member secured to one end of the body or so provided as to be located in front of the transparent body. When the transparent body is mounted within the combustion apparatus, the metallic member is positioned within the combustion flame area or closely adjacent thereto with the transparent body relatively remote therefrom. The metallic member is heated to a red-hot condition upon occurrence of the flame, and readily transmits light to the adjacent end of the transparent body and thus to the opposite end of the transparent body in the vicinity of the viewer, allowing the viewer to instantaneously determine whether or not fuel is actually being burned.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a schematic elevational view of one embodiment of the device of the present invention.

fourth embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a gaseous fuel burner 1 is under combustion such that a flame I1 is being generated, the flame ll being isolated from the eye 3 of the observer or viewer due to the position of partition 2, and employed to isolate the waste gas from the ambient atmosphere. The waste gas is conducted to an exit (not shown) forming a part of the combustion apparatus. Since the material constituting partition 2 is usually opaque, a device for indicating the existence of combustion of the fuel is thus required. The device for indicating fuel combustion and constructed in accordance with the present invention employs a base body 4 in the form of a rod made of transparent glass. A heat-resisting and oxidation-proof metallic wire 5 is secured to one end 41 of the base body 4 which itself terminates just short of the combustion flame 11. The metallic wire 5 is located adjacent to the end surface of the rodlike body 4 and has a portion adapted to be inserted into flame ll generated by the fuel burner I. When the fuel is actually being burned, the metallic wire 5 is rapidly heated by flame ll thereby emitting a light of high brilliance. The thusly generated light passes through the transparent rodlike body 4 from the end 41 to the opposite end 40 as indicated by arrow A and the broken line permitting the COITIIJUSIIOTFCOIldIIIOh of burner 1 to be detected by visually observing light emanating from end 42.

In FIG. I, a metallic wire 5 is employed as the metallic member however, alternatively, a small metallic plate or piece 51 may be employed as shown in the embodiment of FIG. 2 which corresponds in all other respects to the embodiment of FIG. I.

FIG. 3 shows a modified form of the transparent rodlike body 43 whereby due to the rod being bent, the position for observation such as 45 in FIG. 3 may be readily varied.

FIG. 4 shows the combination of a transparent glass rodlike body 44 and an abutting light-conducting, optical, fiber bundle 6 which combination is used in place of the transparent rodlike base body 4 of the embodiment of FIG. I. With the arrangement shown in FIGS. 3 and 4, the position for observation as at 45 and 61 may be readily-displaced as desired.

Several examples carried out in accordance with the present invention are set forth as follows:

EXAMPLE I Each of the constituents consists of oxide of a percentage by weight, respectively, SiO =70 percent, Al,0,=percent, Li =2.8 percent, Ba0==0.4 percent, Zu0=l .6 percent, Mg0=l.8 percent, Sb O =percent, As 0 =pereent, TiO =l.8 percent and ZnO =2.0 percent was mixed together and melted at a temperature of about l,650C so as to obtain a solid glass rod having a diameter of 6 mm. by a mechanical shaping process. The glass rod thus obtained, was cut to alength of 102 mm. and heat treated at a temperature of 850C for 4 hours so as to be transformed into transparent crystallin glass. This transparent crystalline glass possessed a very low coefficient of linear thermal expansion of 6 X 10- cmJcht. C., a high transition point of 820C. and possessed very high transparency. The transparent crystalline glass rod was used as a-transparent base body designated by the numeral 4 iii the device of FIG. 1. A Kanthal A-l wire having a diameter of 0.5 mm. was bent into the position shown in FIG. 1 and used as the metallic wire indicated at 5. The distance between the wire and the end surface of the rodlike body 4 was set to 3 mm. and the wire was fixedly secured to the transparent crystalline glass rod. Commercial town gas was burned by a bunsen burner to generate flame 11. The time period between the insertion of the metallic wire into the flame and the detection of the combustion by the naked eye through the rodlike body was measured. A time period of 2 seconds was noted and the light emanating from the end 42 of the rodlike body was very bright thus facilitating observation.

Similar tests were made using a transparent crystalline glass rod having one end shaped to conical form with an apex angle of about 20. With this prior art type of apparatus, it took about 8 seconds until detection of combustion in the presence of flame was possible by viewing the opposite end of the transparent rod. It is thus readily apparent that the period of time required for possible detection is greatly shortened and at the same time the brightness of the end surface 42 of the light transmitting rod under the system of the present invention is surprisingly superior in comparison with the prior art device. Further, the conically shaped tip of the transparent rod used in the comparison test became milk white during several repetitions of the test. To the contrary, the metallic wire of the present invention showed no change in appearance and no change in performance was noted, thereby proving that the metallic wire in accordance with the present invention when used with a rod whose end is spaced from the combustion flame may be used for a long period without deterioration in performance.

EXAMPLEZ A metallic piece made from a Ni-Cr alloy plate having a trade name Standard NCH 2" and having a size of mm. X 5 mm. and a thickness of 0.2 mm. was used in place of the metallic wire employed in Example 1, as shown in FIG. 2. The results were the same as those obtained in Example 1.

EXAMPLE 3 A transparent crystalline glass rod bent about l30as shown in FIG. 3 was used in place of the transparent rodlike base body 4 employed in Example 1. The results were the same as those obtained with respect to Example 1. The direction of observation however, was readily changed to the position shown in FlG. 3.

EXAMPLE 4 This test was similar to that of Example 1 except that one end of the transparent crystalline glass rod was made thin, that is, of lesser diameter and a light conducting, plastic, optic fiber system under the trade name Chrofon Type l6l0x", manufactured by the Dupont Corporation was bonded by a material known under the trade name Araldite to the reduced diameter or thin end of the transparent crystalline glass rod and this assembly was used in place of the transparent base body 4 employed with the example of FIG. 1. Although the area of the fiber optic bundle at 61 available for observation was thus reduced, the effectiveness of the device was the same as that obtained with the device of Example 1.

Several embodiments have been thus described, but it is apparent to a person skilled in the art that variations and modifications may be effected within the scope and spirit of the present invention. For example, the metallic member may not necessarily be secured to the end of the transparent body, it may be readily secured to the shield plate 2 as long as it is positioned within the flame area or adjacent thereto so that it is readily heated by the combustion flame. Further, a solid transparent rod, a platelike transparent body or a transparent light pipe having a thick wall may be readily used as the transparent base body.

The end of the transparent base body which faces the lightemitting body may be enlarged while the other end from which the light is emitted to the observer may be thinned or reduced in diameter so that the intensity of light emitted from the observation end is readily increased. Further, a thin layer of glass having a low refractive index may be clad to the peripheral surface of the transparent base body. The material constituting the metallic member which emits light when sub- 'ected to the combustion flame must of course be selected rom a heat-resisting and oxidation-proof metal WhlCh WI" not be effected by the combustion flame with the exception of producing or emitting light. It is preferable to use nickelchromium alloy of the type known under the trade name Standard NCH 1, Standard NCH 2", or chrome steel known under the trade name Standard FCH 1, Standard FCl-l 2", or Kanthal wires A-l, Kanthal wire A, Kanthal wire A-250 (1250) or Pyromax as the material constituting the metallic member of the present device. Further, a metallic member whose surface is coated with a ceramic material may be used. As a ceramic material ThO -CeO for example may be employed in conjunction with the metallic member to cause a light of increased brightness or brilliance to be emitted. in case a metallic wire is used as the metallic member, it is preferred to select a wire having a diameter greater than about 0.4 mm. because the wire might be softened due to combustion if the diameter is too small. On the other hand, the diameter of the wire may not be too large because the workability of the wire is reduced and at the same time due to the increased diameter there is created a delay in the wire reaching a condition of emitting light and thus a delay in detection of combustion. The relative location between the light-emitting metallic member, the transparent base body and the burner may be easily determined by experimentation.

We claim:

l. A combustion flame-indicating device for a fuel burner comprising a transparent body positioned at some distance from the fuel burner flame area, and a heat-resisting, oxidation-proof metallic member capable of emitting light in response to combustion positioned in the flame area whereby light is instantaneously emitted by said metallic member upon fuel combustion and is transmitted through said transparent body to an observer at the opposite end thereof, said metallic member being supported. directly in front of said transparent body, within said fuel burner flame area.

2. The indicating device as claimed in claim 1 wherein said metallic member is fixedly secured to the end of said transparent body adjacent said flame area.

3. The indicating device as claimed in claim 1 wherein said transparent body comprises an elongated, solid transparent body in the vicinity of the flame area and a light-indicating fiber optic system operatively connected to the solid body for directing light to an observer optically displaced therefrom.

4. The indicating device as claimed in claim 1 wherein the end of said transparent body adjacent the fuel burner flame area is enlarged in contrast to the end of said body in the vicinity of said observer to permit the intensity of light emitted from the observation end to be increased.

5. The indicating device as claimed in claim 1 wherein said metallic member comprises a wire formed of a material from the group consisting of Ni-Cr alloy, Cr steel, Kanthal and Pyromax.

6. The indicating device as claimed in claim 1 wherein said metallic member is a small, metallic plate formed of one material of the group consisting of Ni-Cr alloy, Cr steel, Kanthal and Pyromax.

7. The indicating device as claimed in claim 1 wherein said transparent body comprises a transparent crystalline glass.

8. The indicating device as claimed in claim 1 wherein said metallic member is coated with a ceramic material to cause a light of increased brilliance to be emitted in response to combustion.

9. The indicating device as claimed in claim 8 wherein said ceramic material comprises ThO -CeO- 

